Joint construction



Patented Sept. 21, 1937 UNiTED STATES PATENT OFFICE 13 Claims.

The invention relates to joints between abutments, such as slabs, blocks, beams and the like, supported in any suitable way preventing excessive rotation.

The invention has for some of its objects to provide a joint construction which will transfer vertical loads principally by tension in either direction from either abutment to the other; to provide a joint construction allowing for expansion and contraction; and to provide a joint construction which reduces the difierence in the vertical deflections of the adjacent end portions of the abutments, or the jump over the joint, to a minimum to thereby avoid bumps. The invention has for other objects to provide an improved joint construction having the simplest possible analytically clear stress distribution in the joint and the abutments; to construct the joint construction to avoid dangerous concentrations of stress in the joint and the adjacent end portions of the abutments resulting from the distribution of forces applied to the adjacent end portions; to provide a joint construction which reduces the efiect of reversal of forces to a minimum; and to provide a jointconstruction which is safe and economical and non-destructive for the adjacent end portions.

I attain these objects by the joint construction illustrated in the accompanying drawing, in which Figure 1 is a plan view of a joint construction showing an embodiment of my invention;

Figure 2 is a cross section on the line 2-2 of Figure 1;

Figure 3 is a perspective View of one of the connecting members.

In the present instance, the joint construction embodying my invention is illustrated as applied to a road pavement having the abutments land 2 which have the adjacent end portions 3 and 4 respectively. The abutments are in the nature of concrete slabs and their end portions are horizontally spaced. Connecting members formed of any suitable material and forming the frame work of the joint construction extend between and are anchored to the end portions 3 and 4 and form therewith the joint construction. There may be any desired number of connecting members, they may be of diiierent sizes and shapes, they may be spaced apart as desired, and they may be arranged in different ways. As shown, there are four connecting members 5, 6, 1, and 8 and they are arranged alternately with the connecting members 5 and 1 arranged in one way and the connecting members 6 and 8 arranged in another way.

The connecting members 5 and l are alike and while each may be an elastic member of any cross section, each in the present instance is formed of sheet metaland is an elastic and flexible'steel sheet having the central portion 9 and the tongues l0 and Il at opposite ends of the central portion, these tongues being formed preferably by longitudinally slitting the end portions of the sheet. The central portion 9 of each sheet extends transversely of the abutments l and 2 in the space between the end portions 3 and 4 and substantially midway therebetween. The tongues ll] of each sheet extend transversely from the upper end of the central portion and are imbedded in the end portion 3. The tongues ll of each sheet extend transversely from the lower end of the central portion and are imbedded in the end portion 4.

The connecting members 6 and8 are like the connecting members 5 and 1, each of the members 6 and 8 being a steel sheet having the central portion l2 and the end tongues l3and M. The central portion l2 of each sheet extends transversely of the abutments l and 2 in the space between the end portions 3 and 4 and substantially midway therebetween. The tongues l3 and E4 of each sheet extend transversely from the upper-and lower ends'respectively of the central portion and are imbedded in the end portions 4 and 3 respectively. I v

It will be seen that certain of the connecting members are anchored or. fastened at theirupper ends to the end portion 3 and'at their lower ends'to the end portion 4 and certain of the connecting members are anchored'or fastened at their upper ends to the end portion 4 and at their lower ends to the end portion 3. It will also be seen that'the central portions of all of the connecting members extend substantially perpendicular to the direction of expansion and contraction and, assuming the abutments to extend horizontally, the central portions are'substantially vertical.

In operation, a vertical load on the top of the end portion 3 of the abutment I is transferred partly to the'support, such as soil, of the end portion and is also transferred partly through the material of the end portion 3 to the tongues I 4 at the lower ends of the central portions l2 of the connecting members 6 and 8. The tongues transfer their load to the central portions placing the latter under tension and the central portions transfer their load to the tongues l3 at their upper ends, which tongues in turn transfer their load into the material of the end portion 4 of the abutment 2. A vertical load acting downward on the top of the end portion 4 of the abutment 2 is transferred in a similar manner through the connecting members 5 and 7 to the end portion 3 of the abutment I.

A vertical load on the top of the end portion 3 may subject the central portions9 of the connecting members Band 1 to compression, while a verticalloadon the top of the end portion 4 may subject the central portions l2 of the connecting members 6 and 8 to compression. To avoid detrimental effect, the connecting members are formed so that they can buckle under these conditions.

With the above construction, vertical load in an upward direction to either abutment will be similarly transferred to the other abutment.

From the above description, it will be seen that vertical loads in either direction are transferred from either abutment to the other predominantly by tension; that small finite expansions and contractions of the joint construction are conditioned by very small elastic deformations of the connecting members and the end portions of the abutments; and that, when the loading is such that the connecting members 5 and I, for example, are extended (or carry no stresses in their central vertical portions) under a vertical downward load-on the top of the abutment 2, the central vertical portions of the connecting members 6 and 8 :may be in compression. The compressive stresses will not exceed the critical stresses in buckling. In other words, the arrangement is such that load upon one of the abutments may cause buckling of certain of the connecting members, but can not have detrimental effect upon these members or the abutments themselves, since the stresses can not go beyond the critical load in bucklingof these members. Therefore, the compressive stresses will be controlled by the buckling of the connecting members and the joint construction will work primarily in tension. By reason of this, the reversal of stresses will be limited on the compression side. It will also be seen that the joint construction provides for expansion and contraction; that, since the vital parts work principally in tension, the joint construction is very'rrigid and effective in the transfer of vertical forces; that the joint construction offers a very small resistance to the transfer of bending moments; and that the effect of reversal of stresses is-minimized by the above limitation of compressive stresses.

For the purpose of keeping the principal stresses low and avoiding dangerous local stress concentrations and also to make the whole picture of stress distribution analytically clear and as simple as possible, I have provided the following features:

The tongues H], II, I3, and M of the connecting members are arranged in several relatively inclined planes and also twisted.

The upper and. lower ends of the central portions of the connecting members are curved to reduce the compression stresses on the material of the 'end portions of the abutments.

Also, the elastic cushions l5, l6, l1, and I8 are provided within the bends or curvatures of the central portions of the connecting members to reduce the stresses depending on the expansion and contraction of the joint construction and the transfer of' load. The cushions are preferably in the nature of elastic tubing, each having a length approximately equal to the width of its connecting member. The cushions are located within the bends at the upper ends of the central portions 9, the cushions IGWithin the bends at the lower ends of the same central portions, the cushions I1 within the bends at the upper ends of the central portions I2 and the cushions l8 within the bends at the lower ends of the same central portions. In the event that elastic cushions are' not used, the spaces occupied by the cushions are filled with the material of the abutments upon which the curved parts of the connecting elements directly transfer their pressure.

Furthermore, the catcher rods I9, 20, 2|, and 22 are provided to prevent the transfer of compression stresses from the central portions of the connecting members into the anchorage portions of the connecting members, thereby preventing the separating of the connecting members from the abutments in a vertical direction and the fracture and scaling off of layers of the material forming the abutments. More particularly, the catcher rods are tongues integral with the connecting members formed by shearing the metal forming the central portions. The tongues l9 and are arranged in pairs with one at each of the opposite side edges of each of the connect ing members 5 and I. These tongues are symmetrically arranged with respect to the longitudinal median planes of the connecting members and are inclined downwardly and inwardly and upwardly and inwardly, respectively, from the upper and lower ends, respectively, of the central portions 9. The tongues 2| and 22 are also arranged in pairs with one at each of the opposite side edges of each of the connecting members 6 and 8. These tongues are also symmetrically disposed with respect to the longitudinal median planes of the connecting members and are inclined downwardly and inwardly and upwardly and inwardly, respectively, from the upper and lower ends, respectively, of the central portions [2. These catcher rods limit the compression only to the central portions of the connecting elements and do not interfere with the extension, compression, or bending of these central portions.

Still further, the connecting members are preferably fastened by suitable means, such as rivets or spot welds, to the elastic cushions l5,

IS, IT, and I8 for the same purpose as the .1

catcher rods. It is apparent that instead of using both the catcher rods and the anchors to the elastic cushions, either may be separately used.

What I claim as my invention is:

1. In a joint construction, the combination of spaced abutments, connecting members between said abutments having portions extending transversely of said abutments and arranged in the space therebetween and other portions extending from different zones of said first mentioned portions and fastened to said abutments, said connecting members transferring load from either abutment to the other predominantly under tension, and elastic cushions between said abutments and first mentioned portions near said second mentioned portions.

2. In a joint construction, the combination of horizontally spaced abutments, elastic connecting members between said abutments having portions extending substantially vertically in the space between said abutments and portions at the upper and lower ends of said first mentioned portions fastened to said abutments, whereby finite expansions and contractions of the joint construction may take place through deformation of said connecting members, and elastic cushions between said abutments and first mentioned portions at the upper and lower ends thereof.

3. In a joint construction, the combination of spaced abutments, connecting members between said abutments having portions extending transversely of said abutments and arranged in the space therebetween and curved at their ends and also having portions extending from the ends of said first mentioned portions and fastened to said abutments, said connecting members transferring load from either abutment to the other predominantly under tension, and elastic tubular members between said abutments and curved end portions of said first mentioned portions.

4. In a joint construction, the combination of horizontally spaced abutments, elastic connecting members between said abutments having portions extending substantially vertically in the space between said abutments and portions at the upper and lower ends of said first mentioned portions fastened to said abutments whereby finite expansions and contractions of the joint construction may take place through deformation of said connecting members, and means for securing saidfirst mentioned portions to said cushions.

5. In a joint construction, the combination of horizontally spaced abutments, connecting members between said abutments having substantially vertical flexible central portions in the space be.- tween said abutments .and transverse portions at the upper and lower ends of said central portions firmly anchored to said abutments, said connecting members transferring vertical load from either abutment to the other predominantly under tension, and means between the ends of said central portions .and said abutments for transferring compressive forces from one to the other independently of said transverse portions.

6. In a joint construction, the combination of horizontally spaced abutments, connecting members between said abutments having substantially vertical flexible central portions in the space between said abutments and transverse portions at the upper and lower ends of said central portions anchored to said abutments, said connecting members transferring vertical load from either abutment to the other predominantly under tension, and catcher rods between the ends of said central portions and said abutments for transferring compressive forces from one to the other independently of said transverse portions.

'7. In a joint construction, the combination of spaced abutments and sheet metal connecting members between said abutments having central portions extending transversely of said abutments and arranged in the space therebetween and end portions anchored to said abutments, said end portions each comprising tongues imbedded in said abutments and extending at angles to each other and twisted.

8. In a joint construction, the combination of spaced abutments and connecting members between said abutments having flexible portions extending transversely of said abutments and arranged in the space therebetween and other portions extending from different zones of said first mentioned portions and firmly fastened to said abutments, said connecting members transferring load from either abutment to the other predominantly under tension and being predominantly extended in their central parts from either the expansion or the contraction of the joint.

9. In a suspension joint construction, the combination of spaced abutments and connecting members between said abutments mutually suspending said abutments in a staggered arrangement and having portions lying in one substantially vertical plane in the neutral position of the joint, and portions at the opposite ends of said vertical portions and in the same plane firmly anchor-ed to the opposite abutments and held from displacement relative thereto, said connecting members transferring the load from either abutment to the other predominately under ten- S1011.

10. In a suspension joint construction, the combination of spaced abutments and elements mutually suspending said abutments in a staggered arrangement and having portions lying in one substantially vertical plane in the neutral position of the joint together with other portions being arranged in the space between the abutments and being firmly fastened with one end to one abutment and with the other end to the other abutment at different levels, the central portions of said elements being flexible to buckle under compression and transferring load from either abutment to the other predominately under tension and their end portions being held from displacement relative to the respective abutments.

11. In a suspension joint construction, the combination of horizontally spaced abutments, connecting members between said abutments mutually suspending said abutments in a staggered arrangement and having portions lying in one substantially vertical plane in the neutral position of the joint and anchor portions at the opposite ends thereof, whereby vertical load is transferred from either abutment to the other predominately under tension, and means between the ends of said central portions and said abutments for transferring compression forces from one to the other independently of said vertical portions.

12. In a suspension joint construction, the combination of spaced abutments and elements mutually suspending said abutments in staggered arrangement, said elements having portions lying in one substantially vertical plane in a space between said abutments, the opposite ends of said portions being anchored to opposite abutments and including tension members for holding said anchored portions from displacement relative thereto, said elements being flexible to buckle under compression and transferring load from either abutment to the other predominately under tension.

13. In a joint construction, the combination of spaced abutments and connecting members between said abutments having portions extending transversely of said abutments and arranged in the space therebetween and other portions extending from the upper and lower ends of said first mentioned portions and both firmly fastened to said abutments partly with the portions extending from the upper end to the left abutment and with the portions extending from the r lower end to the right abutment and partly with the portions extending from the upper end to the right abutment and with the portions extending from the lower end to the left abutment,

these two kinds of connecting members being arranged alternatively along the joint transferring load from either abutment to the other with the one type of the connecting members working predominately in tension and the other type predominantly in compression in their central parts, if the load is transferred from the left abutment to the right abutment and in the opposite way if the load is transferred from the right abutment to the left abutment, and both kinds of connecting members being predominantly extended in their central parts from either the finite expansion or the finite contraction of the joint caused by small deformations of the joint construction.

WYNNE OSCAR FREMONT. 

